1. Field of the Invention
The present invention relates to an automatic chemical analyzer which is capable of determining the plural components of a sample by using the independent reagents for the respective components, and in which the sections of conducting transfer, mixing and determination of the reagents, samples and reaction solution being determined are shared in part or wholly.
2. Description of the Related Art
Analysis of the specific components of a sample is realized by using the reagents which react specifically with the respective components. In the automatic chemical analyzers, it is possible to make determination of the plural items of analysis simultaneously or in parallel with each other by using these different reagents.
However, in the case of an automatic analyzer in which the mechanism of dispensing the sample and reagents, the vessel for carrying out the reaction of the sample with the reagents, the mechanism of stirring the sample with the reagents, etc., are shared in conducting the determination of the plural items of analysis, there may take place an unintended reaction or reactions due to contamination of the respective reaction solutions and reagents, giving rise to errors in the results of determination.
For instance, in case a reagent used in the item of analysis A contains a substance (such as a reaction inhibitor or accelerator) which may participate in the reaction in the item of analysis B, and the determination of the item of analysis A and that of the item of analysis B are conducted successively, if the reagent used in the item of analysis A is contaminated with the reagent used in the item of analysis B, the reaction in the item of analysis A may be caused to start during and proceed simultaneously with the reaction in the item of analysis B, giving rise to errors in the analytical result.
In order to avoid this problem, it has been required for the user to examine beforehand the probability of influence of the contamination and to work out a determination system which can preclude the occurrence of contamination. For instance, a method has been used in which the analysis of item C is interposed between the analyses of item A and item B so that the analysis of item B will not be conducted immediately after the analysis of item A.
In the automatic chemical analyzers, on the other hand, contamination has been avoided by, for instance, a method in which the user previously registers the combinations of the items of analysis where contamination may occur so that the order of analysis is changed automatically, or by incorporating an expedient (such as cleaning with water or detergent) for inhibiting the occurrence of contamination. But it has been the user's obligation to conduct an investigation of the influence of contamination.
Also, when a new item (or items) of analysis is (are) added or the formulation is changed with introduction of a new system, it is necessary to conduct an investigation of the influence of contamination whenever such addition of item(s) or change of formulation is made. For conducting an investigation of the influence of contamination, it needs to set the conditions under which the contamination can actually occur, so that the user must be well acquainted with the operating program, etc., of the system and is required have a very high level of knowledge and technical skill.
Actually, however, most of the users are unable to implement setting of the determination conditions for the investigation of the influence of contamination and to make the analysis of the determination results. Thus, even though using an automatic chemical analyzer having a function to shun the influence of the registered contamination, it has been probable that the influence of contamination be not avoided in the analysis and the false result be reported.
The devices capable of collecting data on cross-contamination by the reagents with ease are disclosed in JP-A-5-240867, JP-A-7-270428, etc.
In JP-A-5-240867 is disclosed a system which memorizes an analysis request pattern with the order of analysis for checking cross-contamination by the reagent dispenser and cells in a predetermined number of channels, and assigns the channels to the respective items of analysis, allowing anyone to easily obtain data on cross-contamination by the reagents.
However, it is likely that an automatic chemical analyzer, in long-time use, would become unable to sufficiently perform its function to inhibit the generation of contamination due to accumulation of contaminants or trouble in the system, causing errors in the result of determination by the contamination which does not occur in the normal state.
In the existing circumstances, it is necessary to detect the change of the state of the apparatus by checking the apparatus or finding the false data of determination on the user's part, and the reliability of the analytical result depends on the user's faculty. Particularly, in case the trouble advances gradually, it is likely that the user fails to notice abnormity of the apparatus and the false determination result is accepted.